Okay, I'll try posting again. This is just my two cents, and in no way is an expert opinion on the matter. I believe there are certain energies in the universe. Christians (and other pluralists) have broken these down into Dark and Light/ Good and Evil. If they can't understand something, they tend to place it in the "evil" or scary category. In the case of the "scariest places", I have to agree with the previous poster who felt that it was exacerbated by the power of suggestion. But if there are earthbound spirits in that place, I believe it to be the residue of people's psyches that were so brutalized there that a portion of "them" go timprinted there. Their essences, I believe have gone on. However, like a photograph, or hologram, some residual energy remains to "tell" their gruesome stories.
As I said that is just my two cents. I watched the first half of the show until I couldn't stand it anymore (the guy harangueing the poor guy who couldn't stop his nervous laughter) It was just a little too silly. But an interesting concept.
Just two cents from Bridgette (who believes very much that there is a scientific explanation for EVERYTHING--even if it turns out to be stranger than fiction)